TSV Wafer Thinning Controlling Method and System

Abstract

A TSV wafer thinning controlling method and system is provided, which can improve the accuracy of the wafer thinning technique. The system includes a chuck table used for carrying a wafer and a grinding device used for thinning the wafer; and further includes: an infrared sensor equipped on the chuck table or grinding device, and a measurement feedback system connected with the infrared sensor and the grinding device; wherein, the infrared sensor comprises an infrared emitting and receiving circuit, signal amplifying and filtering circuit and a data processor.

1 . A TSV wafer thinning controlling method, applied to a thinning process of a TSV wafer, wherein, an infrared sensor is set on a grinding device and the method comprises:
 setting an initial value of the distance from the backside of a TSV wafer to the bottom of via-holes;   launching infrared rays and receiving reflected waves;   filtering reflected waves of the bottom of the via-holes in the TSV wafer and calculating the distance from the backside of the TSV wafer to the bottom of the via-holes during the thinning process;   comparing the distance from the backside of the TSV wafer to the bottom of the via-holes during the thinning process with the initial value;   generating a signal to terminate the thinning processing when the distance from the backside of the TSV wafer to the bottom of the via-holes during the thinning process equal to the initial value.   
     
     
         2 . The method of  claim 1 , wherein, the thinning process comprises one or more processes from coarse grinding, fine grinding and polishing 
     
     
         3 . The method of  claim 1 , wherein, the initial value is set as smaller than the thickness of the TSV wafer before thinning 
     
     
         4 . The method of  claim 3 , wherein, the initial value is larger than 1 μm. 
     
     
         5 . The method of  claim 1 , further comprising:
 calibrating the infrared sensor.   
     
     
         6 . A TSV wafer thinning controlling system comprising a chuck table used for carrying a wafer and a grinding device used for thinning the wafer; wherein, the system further comprises:
 an infrared sensor equipped on the chuck table or grinding device,   a measurement feedback system connected with the infrared sensor and the grinding device;   wherein, the infrared sensor comprises an infrared emitting and receiving circuit, signal amplifying and filtering circuit and a data processor.   
     
     
         7 . The system of  claim 6 , further comprises: a measurement window set at the bottom of the infrared sensor. 
     
     
         8 . The system of  claim 7 , wherein, the measuring window comprises a blowing device or deionized water injection device. 
     
     
         9 . The system of  claim 6 , wherein, the lowest position of the infrared sensor is higher than the lowest position of the grinding device. 
     
     
         10 . The system of  claim 6 , further comprising: a protective tape set on the front side surface of TSV wafer. 
     
     
         11 . The system of  claim 6 , wherein the grinding device comprises a transmission shaft and a chassis for fixing and connecting. 
     
     
         12 . The system of  claim 11 , wherein the chuck table comprises three carrying units, and/or the chassis comprises several grinding units. 
     
     
         13 . The system of  claim 11 , wherein the infrared sensor is fixed on the chassis of the grinding device through an installation unit. 
     
     
         14 . The system of  claim 6 , wherein the infrared sensor is fixed directly onto the grinding device. 
     
     
         15 . The method of  claim 6 , wherein, the measuring frequency of the infrared sensor is equal to or larger than  50  times/sec. 
     
     
         16 . The method of  claim 6 , wherein, the infrared sensor emits near infrared wave.